1. Field of the Invention
This invention relates generally to communications networks, and more particularly to monitoring and tracking port-to-link configurations within connection-oriented communications networks.
2. Discussion of the Related Art
Communications networks provide a capability for one device, referred to as a source, to transmit data to another device, referred to as a destination. Among the conventional types of communications are connection-oriented communications and connectionless communications.
In connection-oriented communications, a logical association is established between the source and the destination, so that several separate groups of data may be sent along the same path that is defined by the logical association. This is distinguished from connectionless communications, in which the source transmits data to the destination in an unplanned fashion and without prior coordination. In connectionless communications, each frame of data is transmitted from the source to the destination in a manner independent from the manner in which other frames are transmitted from the source to the destination. Bridges and routers are commonly used in connectionless communications.
Three phases generally occur during connection-oriented communications, including connection establishment, data transfer, and connection termination. These three phases together are commonly called a session, which may be monitored and controlled by a central authority. In the connection establishment phase, the first time a source has data to be sent to a destination, a logical association, also called the connection or a path, is established between the source and the destination. The connection defines elements and connections between the elements, for example, switches between the source and the destination, and the ports of the switches through which the data will pass from the source to the destination.
A switch, and other devices similar in operation to a switch, may be referred to as a node, intermediate system, interface message processor, or gateway. A port is an interface on a switch or similar device that provides a physical communication path to other devices, for example to other ports of other switches. During the data transfer phase, data is transmitted from the source to the destination along the connection, which includes the port-to-port connections of the switches. After a certain amount of time, or at the occurrence of a certain event, the session enters the connection termination phase, in which the connection is terminated, and the elements which made up the connection are freed to support other connections.
There may be a large number of connections which represents a very large and complex amount of connection information for a central authority to monitor. Additionally, some connections may fail, due to electrical problems or physical or logical removal of any of the elements which make up the connection. For example, a switch may be removed for maintenance or to achieve a more advantageous physical arrangement for other connections. It would thus be desirable to provide a monitoring capability for tracking a large number of connections in a connection-oriented communications network.